Ethereum is still like 500x. Of course, it can happen. But It depends on BTC move. If we dip like 5300$, all coins are going to be bloody red.
It is not always depended on the bitcoin price movement even though they have the majority of pairings and support they have their own price movements, btc can influence but the altcoins individual schemes and development can move the price even bigger or even lower for instance like the Op said about ICO's as it can drag the price down due to the campaigns pacing, eligibility and price.